AP Bio: Unit 3 Cells + Transport

Cells

1. What are the three basic principles of cell theory?
   a. All living things are made up of one or more cells
   b. The cell is the building block of structure and organization in organisms
   c. Cells are made of pre-existing cells
2. Why is it advantageous for a cell to be small?

• It helps with exchange of materials (more exit points)

1. Explain the endosymbiotic theory.
   a. A prokaryotic cell was engulfed, and it became a mitochondrion and then a chloroplast
   b. It explains the evolution of mitochondria and chloroplasts
2. Write down part of cell and its corresponding function.
   a. Nucleus – store the cell’s DNA, controls activities of the cell, makes RNA for ribosomes
   b. Ribosome – makes proteins, bound (for outside) on rough ER, free (inside) cytoplasm, makes polypeptides, RNA -> protein
   c. Mitochondria – powerhouse of the cell, makes ATP, endosymbiotic theory
   d. Chloroplast – in plants only, makes chlorophyll, endosymbiotic theory
   e. Smooth endoplasmic reticulum – makes lipids, no ribosomes, stores calcium, detoxifies
   f. Rough endoplasmic reticulum – has ribosomes, makes proteins (secondary and tertiary structure)
   g. Golgi body – sorts, modifies, packages, distributes (outside), near ER
   h. Vacuole – stores and transports materials and waste with cell
   i. Lysosome – breaks things down, hydrolytic enzyme, break down food, autophagy (breakdown old cell parts), apoptosis (cell death)
   j. Centriole – near nuclear envelope, organizes microtubules, help determine the location of nucleus and other organelles
   k. Microtubule – largest; used as tracks for movement; flagella and cilia
   l. Microfilament – thinnest; makes up muscles; used by amoebas to move
   m. Intermediate filament – middle sized; hold cell structure and anchor organelles
   n. Flagella – enables movement, whiplike structure
   o. Cell membrane – the membrane surrounding the cell, composed of phospholipid bilayer
   p. Cytoplasm – the region inside the cell except for the nucleus
3. Name the organelles that are a part of the endomembrane system
   a. Nucleus -> ER -> vesicle -> golgi -> vesicle -> out cell membrane
4. Trace the path of a protein from rough ER to the plasma membrane.
   a. Rough ER -> golgi body -> vesicle -> cell membrane
5. What is a motor protein?
   a. Responsible for the active transport of most proteins and vesicles, walk on microtubules, carry vesicles

Transport

1. Describe the fluid mosaic model of membrane structure.
   a. Fluid = moves - Mosaic = many parts
   b. The surface appears mosaic because of the proteins in the phospholipids and fluid because the proteins can drift about in the phospholipids

2. Tell how the phospholipids are arranged in the plasma membrane. What other lipid is present in the membrane, and what functions does it serve?
   a. In two layers called a Phospholipid bilayer, a hydrophobic interior and a hydrophilic exterior
   b. Sphingomyelin plays a role in cell signaling pathways

3. What is cell signaling and how does it occur?
   a. The way that cells communicate with other cells
   b. How a gland in the brain can react to external stimuli and respond, the gland releases a hormone which activated a response in body systems to coordinate a response

4. Define diffusion. What factors can influence the rate of diffusion? What substances can diffuse through a differently permeable membrane?
   a. Particles move from high concentration to low concentration until balanced (no energy required). Facilitated diffusion helps it distribute faster, protein helper makes it cross; water (energy required).

5. Define osmosis. Describe verbally and with drawing what happens to an animal cell and plant cell when placed in isotonic, hypotonic, and hypertonic solutions.
   a. The movement of water molecules from a solution of high concentration to low concentration through a semi permeable membrane
   b. Animal cell: isotonic – normal (water equal on both sides), hypotonic – lysed (so much water inside, it bursts), hypertonic – shriveled (to little water inside)
   c. Plant cell: isotonic – flaccid (drooping), hypotonic – turgid (swell up but not burst), hypertonic – Shriveled/plasmolyzed (loses water and shrinks)

6. Compare and contrast facilitated diffusion with active transport.
   a. They both occur along a concentration gradient from high concentration to low concentration, but facilitated diffusion does not require energy, and active transport does require energy (assisted by enzymes)

7. Explain how the sodium potassium pump works.
   a. Moves sodium and potassium ions against large concentration gradients, low to high concentration

8. What are the three methods of endocytosis.
   a. Phagocytosis (cell eating),

   b. pinocytosis (cell drinking)

   c. receptor mediated (specific receptor to catch a substance)

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